Revert EnableClose() removal and related crash fixes. I don't understand the crashes here, and th...

ui/aura_shell/toplevel_frame_view.cc

Index: ui/aura_shell/toplevel_frame_view.cc
===================================================================
--- ui/aura_shell/toplevel_frame_view.cc	(revision 113407)
+++ ui/aura_shell/toplevel_frame_view.cc	(working copy)
@@ -161,6 +161,11 @@
     return HTNOWHERE;
   }
 
+  // Updates the enabled state of the close button.
+  void EnableClose(bool enable) {
+    close_button_->SetEnabled(enable);
+  }
+
   // Overridden from FrameComponent:
   virtual bool IgnoreEventsForPoint(const gfx::Point& point) OVERRIDE {
     gfx::Point translated_point(point);
@@ -396,6 +401,10 @@
   // Nothing.
 }
 
+void ToplevelFrameView::EnableClose(bool enable) {
+  caption_->EnableClose(enable);
+}
+
 void ToplevelFrameView::ResetWindowControls() {
   NOTIMPLEMENTED();
 }